P1253553558bFhuM

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Designing Hydrologic Modeling Studies to Support
Diverse Climate Change Planning Needs in the
Columbia River Basin
Alan F. Hamlet Amy K. Snover Kurt Unger Philip
W. Mote Dennis P. Lettenmaier JISAO/CSES
Climate Impacts Group Dept. of Civil and
Environmental Engineering University of
Washington WA State Department of Ecology
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Simulated Changes in Natural Runoff Timing in the
Naches River Basin Associated with 2 C Warming

• Impacts
• Increased winter flow
• Earlier and reduced peak flows
• Reduced summer flow volume
• Reduced late summer low flow

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PNW Pilot Climate Change Planning Efforts
West Side Cascades Partnerships Portland Water
Bureau Seattle Public Utilities Tualitin
Basin White River-Lake Tapps Snohomish River
Basin King Co. Columbia Basin Partnerships North
west Power and Conservation Council (BPA) US
Bureau of Reclamation (Boise) Seattle District
Corps of Engineers Idaho Department of Water
Resources
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Recession of the Muir Glacier
Aug, 13, 1941
Aug, 31, 2004
Image Credit National Snow and Ice Data Center,
W. O. Field, B. F. Molnia http//nsidc.org/data/gl
acier_photo/special_high_res.html
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Collapse of the Larsen B Ice shelf, Antarctica
March 5, 2002
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Bark Beetle Outbreak in British Columbia
(Figure courtesy Allen Carroll)
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Trends in April 1 SWE 1950-1997
Mote P.W.,Hamlet A.F., Clark M.P., Lettenmaier
D.P., 2005, Declining mountain snowpack in
western North America, BAMS, 86 (1) 39-49
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As the West warms, spring flows rise and summer
flows drop Stewart IT, Cayan DR, Dettinger MD,
2005 Changes toward earlier streamflow timing
across western North America, J. Climate, 18 (8)
1136-1155
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An Opportunity to Provide Improved Access to
Hydrologic Scenarios for Planning
As the public and professionals in the water
management and policy arenas have become
increasing concerned about the impacts of climate
change on PNW water resources, demand for
hydrologic scenarios suitable for planning
purposes at a range of spatial scales has
increased dramatically. Currently there does not
exist an up-to-date, comprehensive, and
self-consistent data base of hydrologic scenarios
for the Columbia River basin that is suitable for
the range of planning activities the Climate
Impacts Group is being asked to support.
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WA House Bill 2860

• 16 Million for studies related to enhancing
  water supplies in the Columbia River basin for
  irrigation and municipal water supply.
• Up to 200 Million for implementing improvements
  identified by these studies.
• Answers to FAQ regarding WA 2860 from the
  Department of Ecology website
• http//www.ecy.wa.gov/pubs/0611014.pdf

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Schematic of a Typical Water Planning Framework
Observed Streamflows
Planning Models
System Drivers
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Schematic of Climate Change Water Planning
Framework
Observed Streamflows
Planning Models
Altered Streamflows
Climate Change Scenarios
System Drivers
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The Need to Encompass Multiple Spatial Scales
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Large Scale Planning Studies

• Examples
• Hydro System Performance
• Flood Control
• Main Stem ESA
• Transboundary Issues
• Large-Scale Irrigation Impacts

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Medium Scale Planning Studies

• Examples
• Water Supply Planning
• Yakima Basin
• Okanogan Basin
• Methow
• Walla Walla Basin

WA State Water Resources Inventory Areas
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3.2C
C
1.7C
0.7C
1.2-5.5C
0.9-2.4C
Observed 20th century variability
0.4-1.0C
Pacific Northwest
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-1 to 3
6
2
1
Observed 20th century variability
-2 to 21
-1 to 9
Pacific Northwest
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Result Daily Precipitation, Tmax, Tmin 1915-2003
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Schematic of VIC Hydrologic Model and Energy
Balance Snow Model
6 km
1/16th Deg.
PNW
6 km
Snow Model
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Streamflow Locations Currently Under Consideration
Blue Large Scale Planning Sites Green Snake
River Sites Red Additional Sites in
WA Partnerships with OR, ID, and BC are being
discussed with the intent to extend the number of
sites in these areas.
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Alternate Approach DHSVM

• Developed in the
• UW Land Surface
• Hydrology Research
• Group at UW for over
• a decade
• a research tool, also
• is used operationally
• applied to small
• catchments
• DHSVM Distributed Hydrology-Soil-Vegetation
  Model

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Medium Scale Planning Studies
WA State Water Resources Inventory Areas
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Some Potential Advantages of DHSVM Approach

• Increased spatial resolution down to the
  watershed scale
• Increased temporal resolution (high and low flow
  extremes)
• Water temperature simulations
• Simple ground water scheme improves base flow
  simulations
• Future access to sediment transport capability
  (research)

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Proposed Downscaling Approaches
Statistical Downscaling (GCM) 10
scenarios Dynamic Downscaling (nested MM 5) 2
scenarios Improvements in downscaling
techniques will be implemented to allow
evaluation of daily effects on flooding and low
flow events.